The distance is based on voltage loss, so the further away you are the larger the wire gauge will need to be. Your electrician should be able to do a voltage loss calculation for you. Or if you call us with all the information we are happy to help.
No, unfortunately it's based on voltage loss not wattage loss. Upsizing the driver does not change the distance from the driver to the start of the ribbon.
Our magnetic series are max load rated, all of our other versions are recommended to stay around 80% full load for commercial projects and 90% full load for residential products.